/**
 * Based on http://www.emagix.net/academic/mscs-project/item/camera-sync-with-css3-and-webgl-threejs
 */

class CSS3DObject extends THREE.Object3D {
  constructor(element = document.createElement( 'div' )) {
    super();

    this.isCSS3DObject = true;

    this.element = element;
    this.element.style.position = 'absolute';
    this.element.style.pointerEvents = 'auto';
    this.element.style.userSelect = 'none';
    this.element.setAttribute( 'draggable', false );


    this.addEventListener('removed', function () {
      this.traverse(function (object) {
        if ( object.element instanceof Element && object.element.parentNode !== null ) {

					object.element.parentNode.removeChild( object.element );

				}

      });
    });
  }

  copy(source, recursive) {
    super.copy(source, recursive);

    this.element = source.element.cloneNode(true);

    return this;
  }
}

CSS3DObject.prototype.isCSS3DObject = true;

class CSS3DSprite extends CSS3DObject {
  constructor(element) {
    super(element);
    this.isCSS3DObject = true;
    this.rotation2D = 0;
  }

  copy(source, recursive) {
    super.copy(source, recursive);

    this.rotation2D = source.rotation2D;

    return this;
  }
}

CSS3DSprite.prototype.isCSS3DSprite = true;

//

const _matrix = new THREE.Matrix4();
const _matrix2 = new THREE.Matrix4();

class CSS3DRenderer {
  constructor() {
    const _this = this;

    let _width, _height;
    let _widthHalf, _heightHalf;

    const cache = {
      camera: { fov: 0, style: '' },
      objects: new WeakMap(),
    };

    const domElement = document.createElement('div');
    domElement.style.overflow = 'hidden';

    this.domElement = domElement;

    const cameraElement = document.createElement('div');

    cameraElement.style.transformStyle = 'preserve-3d';
    cameraElement.style.pointerEvents = 'none';

    domElement.appendChild(cameraElement);

    this.getSize = function () {
      return {
        width: _width,
        height: _height,
      };
    };

    this.render = function (scene, camera) {
      const fov = camera.projectionMatrix.elements[5] * _heightHalf;

      if (cache.camera.fov !== fov) {
        domElement.style.perspective = camera.isPerspectiveCamera ? fov + 'px' : '';
        cache.camera.fov = fov;
      }

      if (scene.matrixWorldAutoUpdate === true) scene.updateMatrixWorld();
      if (camera.parent === null && camera.matrixWorldAutoUpdate === true ) camera.updateMatrixWorld();

      let tx, ty;

      if (camera.isOrthographicCamera) {
        tx = -(camera.right + camera.left) / 2;
        ty = (camera.top + camera.bottom) / 2;
      }

      const cameraCSSMatrix = camera.isOrthographicCamera ?
				'scale(' + fov + ')' + 'translate(' + epsilon( tx ) + 'px,' + epsilon( ty ) + 'px)' + getCameraCSSMatrix( camera.matrixWorldInverse ) :
				'translateZ(' + fov + 'px)' + getCameraCSSMatrix( camera.matrixWorldInverse );

			const style = cameraCSSMatrix +
				'translate(' + _widthHalf + 'px,' + _heightHalf + 'px)';

      if (cache.camera.style !== style) {
        cameraElement.style.transform = style;

        cache.camera.style = style;
      }

      renderObject(scene, scene, camera, cameraCSSMatrix);
    };

    this.setSize = function (width, height) {
      _width = width;
      _height = height;
      _widthHalf = _width / 2;
      _heightHalf = _height / 2;

      domElement.style.width = width + 'px';
      domElement.style.height = height + 'px';

      cameraElement.style.width = width + 'px';
      cameraElement.style.height = height + 'px';
    };

    function epsilon(value) {
      return Math.abs(value) < 1e-10 ? 0 : value;
    }

    function getCameraCSSMatrix(matrix) {
      const elements = matrix.elements;

			return 'matrix3d(' +
				epsilon( elements[ 0 ] ) + ',' +
				epsilon( - elements[ 1 ] ) + ',' +
				epsilon( elements[ 2 ] ) + ',' +
				epsilon( elements[ 3 ] ) + ',' +
				epsilon( elements[ 4 ] ) + ',' +
				epsilon( - elements[ 5 ] ) + ',' +
				epsilon( elements[ 6 ] ) + ',' +
				epsilon( elements[ 7 ] ) + ',' +
				epsilon( elements[ 8 ] ) + ',' +
				epsilon( - elements[ 9 ] ) + ',' +
				epsilon( elements[ 10 ] ) + ',' +
				epsilon( elements[ 11 ] ) + ',' +
				epsilon( elements[ 12 ] ) + ',' +
				epsilon( - elements[ 13 ] ) + ',' +
				epsilon( elements[ 14 ] ) + ',' +
				epsilon( elements[ 15 ] ) +
			')';
    }

    function getObjectCSSMatrix(matrix) {
      const elements = matrix.elements;
			const matrix3d = 'matrix3d(' +
				epsilon( elements[ 0 ] ) + ',' +
				epsilon( elements[ 1 ] ) + ',' +
				epsilon( elements[ 2 ] ) + ',' +
				epsilon( elements[ 3 ] ) + ',' +
				epsilon( - elements[ 4 ] ) + ',' +
				epsilon( - elements[ 5 ] ) + ',' +
				epsilon( - elements[ 6 ] ) + ',' +
				epsilon( - elements[ 7 ] ) + ',' +
				epsilon( elements[ 8 ] ) + ',' +
				epsilon( elements[ 9 ] ) + ',' +
				epsilon( elements[ 10 ] ) + ',' +
				epsilon( elements[ 11 ] ) + ',' +
				epsilon( elements[ 12 ] ) + ',' +
				epsilon( elements[ 13 ] ) + ',' +
				epsilon( elements[ 14 ] ) + ',' +
				epsilon( elements[ 15 ] ) +
			')';

			return 'translate(-50%,-50%)' + matrix3d;
    }

    function renderObject(object, scene, camera, cameraCSSMatrix) {
      if ( object.isCSS3DObject ) {

				const visible = ( object.visible === true ) && ( object.layers.test( camera.layers ) === true );
				object.element.style.display = ( visible === true ) ? '' : 'none';

				if ( visible === true ) {

					object.onBeforeRender( _this, scene, camera );

					let style;

					if ( object.isCSS3DSprite ) {

						// http://swiftcoder.wordpress.com/2008/11/25/constructing-a-billboard-matrix/

						_matrix.copy( camera.matrixWorldInverse );
						_matrix.transpose();

						if ( object.rotation2D !== 0 ) _matrix.multiply( _matrix2.makeRotationZ( object.rotation2D ) );

						object.matrixWorld.decompose( _position, _quaternion, _scale );
						_matrix.setPosition( _position );
						_matrix.scale( _scale );

						_matrix.elements[ 3 ] = 0;
						_matrix.elements[ 7 ] = 0;
						_matrix.elements[ 11 ] = 0;
						_matrix.elements[ 15 ] = 1;

						style = getObjectCSSMatrix( _matrix );

					} else {

						style = getObjectCSSMatrix( object.matrixWorld );

					}

					const element = object.element;
					const cachedObject = cache.objects.get( object );

					if ( cachedObject === undefined || cachedObject.style !== style ) {

						element.style.transform = style;

						const objectData = { style: style };
						cache.objects.set( object, objectData );

					}

					if ( element.parentNode !== cameraElement ) {

						cameraElement.appendChild( element );

					}

					object.onAfterRender( _this, scene, camera );

				}

			}

			for ( let i = 0, l = object.children.length; i < l; i ++ ) {

				renderObject( object.children[ i ], scene, camera, cameraCSSMatrix );

			}
    }
  }
}

export { CSS3DObject, CSS3DSprite, CSS3DRenderer };
